I need you for an experiment
by Black Fullmoon
Summary: Sherlock needs John for collecting data for a case, but it isn't the kind of experiment John thinks. Slash, no romance


**Wow, my first lemon! I hope it isn't too terrible. I like Johnlock, but I'm not such a great fan, so it's possible that I'll publish only this one (or maybe others, since I like smut and all that stuff... ) After this talking that no one wants to read, I'm sorry for the mistakes but I'm not English. R&R please  
Disclaimer: I'm not the owner of this charachters, despite I'd really like**

Sherlock was observing the crime scene. A dead man was laying on the ground, open arms, face down, head covered in blood. At the first exam, his death was probably the result of something hard thrown to his head.  
- So freak? - Donovan asked watching as Sherlock took his I-know-everything-and-you-don't face.  
- So our man was taken by surprise, probably he was with someone he trusted who hit him while he wasn't watching. There's premeditation and the murderer is probably his lover, someone around 1.75m tall and 75kg heavy, right handed. The victim didn't want to leave his wife, so his lover killed him in one of theirs secret meetings - Sherlock explained.  
- And who is our murderer? - asked Lestrade.  
- At the moment, I'm not sure. I'll tell you by tomorrow noon. John, come - Sherlock walked away followed by the army doctor.  
- You're not sure? - asked John looking his friend.  
- You heard well John, I'm not sure. The fact is the dead was bisexual, and I don't know if his lover was male or female, things I'd know if those idiots working for Scotland Yard haven't make a mess with the scene. Now I have to do an experiment to be sure of my theory, and you're gonna help me -  
- What kind of experiment? - asked John confused.  
- You'll see - Sherlock didn't speak for all the way back to Baker Street. As they arrived, he went in his room and locked the door. John sighed and sit on the couch, taking his laptop and starting write on his blog.  
It was almost nine when Sherlock returned to the living room.  
- God, no - John sighed.  
- No what? -  
- You have a look I don't like at all. Tell me that we don't have to do anything dangerous -  
- I think you may don't like, but you have to help me - John passed his hand through his hair. - I'm listening Sherlock -  
- I know it. So, our murderer prints were quite unusual. Probably our two men, cause I'm sure the lover is a man, had sex before the murder and the murderer was the bottom. The dead put an interesting amount of strenght and our bottom couldn't walk properly -  
- Fascinating. And? -  
- Stay calm John. Due to this walking problem, my first stimes of the man's height and weight could be wrong. I need more data to calculate exactly, data that I can find in any man who had sex with a man similar to our dead -  
- I still don't understand - Sherlock sighed.  
- John, you've got almost the same phisique of the dead. The fastest way I have to find those data is you fucking me - John took a few seconds to elaborate.  
- You're joking - said in the end.  
- I never joke - John stared at him with wide eyes.  
- Come on Sherlock... You... I... Oh, God's sake, you cannot ask me that! -  
- Why not? - Sherlock questioned. From the look in his eyes John understood he was complitely serious.  
- We are friends Sherlock! Friends don't have sex with each other! -  
- Sarah is your friend too and you had sex with her. And not only with her -  
- But it's different! I'm not even gay Sherlock! - John protested.  
- I'm asexual but I'm asking you to fuck me, it isn't that different -  
- Sherlock... Do you know what are you talking about? -  
- John, you have to know that I'm not stupid, I know what sex is -  
- One thing is knowing, another is doing it! With your asexual best friend! -  
- I'm not exactly virgin, I had sex with someone at Uni. In fact, I admit I have fucked four different girls and also a boy. Only, I need you to be top to collect some data. If the thing can make you feel better, I have a drug that will make you forget all the past twelve hours before you take it. Now get up and come in my room - John didn't make a move. Apart for the confession of having that amount of sexual life you'd never imagine Sherlock would be interested in, the detective words literally made John's brain short-circuited. Before he could even realized it, Sherlock dragged him into his room.  
- Wait! What... - John's voice was cut by Sherlock's lips pressed firmly on his own. They were extrimely soft. John's mouth remained open for the shock, and Sherlock quickly put his tounge in it. His taste was strange, of something John didn't recognize. After almost a minute finally John sent all his worries to hell and kissed Sherlock back, their tounges fighting in each other's mouth.  
When they broke apart, Sherlock's mouth went on John's neck, licking and kissing gently. John let out a moan. Sherlock pushed him til his legs hit the bed, and then he fell behind with Sherlock on him. The detective approached to take John's jumper of. His fingers were cold against John's chest. The younger man's mouth left John's neck to allow the jumper to pass.  
- What are you doing? - John asked, watching the detective undoing his shirt and feeling his own trousers going tight.  
- Undressing. I'd prefer to just being fucked and have my data, but this will probably make you more confortable - the purple shirt finally was tossed to the ground, leaving exposed Sherlock's pale chest.  
The detective folded himself on John, liking his collarbones and descending slowly. John's skin was burning and for what he could see also Sherlock was getting aroused. His pupils were dilated and his breath was getting heavy. When he bit on John's nipple the doctor let out a low groan and sinked his hands in Sherlock's hair. That was really good.  
After sucking both of John's nipples, Sherlock's tounge went down, down, down, til he arrived at John's jeans. Now there was a very visible bulge and Sherlock's mouth so near to John's erection was getting it even harder.  
Sherlock's fingers went to unzipping and unbottoning the jeans, taking them down. Now John's hard member was covered only by a thin layer of grey cloth, wet with pre-cum. Sherlock stared at it, and then passed his tounge on the lenght. John almost screamed.  
- God, Sherlock... - his fingers clenched around the black curls, forcing Sherlock's head to remain there. The man passed again his tounge on the other's erection, earning half-screams and moans. Suddenly John hadn't anything to complain about the situations. He felt his orgasm building, he was so fuckin' damned close...  
And then Sherlock pulled away. John groaned in frustration. The detective kissed him pasionately. - Remember our experiment John - he whispered. John swallowed. He put his hands on Sherlock shoulders, and inverted their positions. Now he was on top of Sherlock, the detective's eyes now half filled with lust, his face covered in sweat, curls stick to his forhead. He barely recognized his always cold and distant friend.  
- John... - his name came out as a moan.  
- I remember, but I, um, never been with a male you know, and... -  
- Shut up and take my trousers down - John quickly did as ordered. Sherlock's pants seemed too small for the big bulge on them. John leaned down to kiss Sherlock's lips. It really felt strange to have sex with him. Inadvertitantly, John made his cover erection rub against Sherlock's one. Both of them let out a moan of pleasure.  
- Sherlock... You really want me to... To do that? - John moaned.  
- Of course, I need data remember? - John nodded and took down his pants. Then proceeded removing Sherlock's. It sent a chill to him to see a cock. And not exactly a little one.  
- What should I do? -  
- Lick your fingers, then put it in me. One at time. Trust me -  
- I feel I'll regret doing this - John put his fingers in mouth and covered them with saliva. When he thought it was enough, he started pull one in Sherlock's entrance. It was so tight and hot. He moved his finger for a while, before entering a second and scizzoring them. He saw Sherlock's discomfort and serched to that spot that would have make him feel better. He knew he found it when Sherlock let out a sort of growl, arching his back. John prepareted him for another minute, then pulled out and put his cock at Sherlock's entrance.  
- I think this will hurt you -  
- Of course it will - John breated deeply and then trusted slowly in Sherlock. He stopped when he was full inside.  
- Are you alright? - he asked, seeing Sherlock's painful face.  
- Y-yeah, just don't move - easier to say than to do. John felt like he was going to explode, and mentally thanked someone when Sherlock nodded. He started moving slowly, searching for the same spot of before. Didn't take long to find it.  
- John go harder! - Sherlock's request get John even more aroused. He trusted in the detective harder and faster, hitting that spot and making Sherlock start to stroke himself.  
- SHERLOCK! - he trusted one last time, spilling his seed in Sherlock. The detective arched his back, coming right after. John let himself fall next Sherlock, breathless.  
- You... You'll kill me one day... I can't... I can't belive you made me do that... Having sex with my best friend... Oh God... -  
- You enjoyed that I think - said Sherlock with a smirk. John blushed.  
- Um, yes... But did you really... Need it? -  
- It make my case easier. However, I'm asexual but not so much. I do enjoy have sex sometimes. Not often, but it passed two years since last time and a part of me started to miss it - John stared at him. Sherlock Holmes was admitting he enjoy have sex sometimes? Was the world started to rotate the other way?  
- Come on John. I'm not proud of it, but somewhere there's still a part of me that has human insincts. By the way, you want that drug or you prefer to remember? - John considered the possibilities. At the moment he was still a bit confused, but he knew that knowing he had sex with a man, who was his best friend and despite all the respect and admiration and all he didn't love would really desturbe him.  
- Gimme that thing -  
- Good. Go wash yourself and then go to your room. I'll be there with the drug - John nodded and did as ordered. When he arrived in his room, he found Sherlock with a glass full of a strange liquid.  
- Is that thing legal? -  
- No. Drink it and go to bed, you'll sleep for a while - John nodded and drinked. The prossimity of Sherlock's body made him blush. He almost istantanely felt his head spinning and fell asleep.

When John woke up, he felt a terrible headache. He was tired but the clock signed two in the afternoon. He tried to remember what happened the day before, but he didn't remember anything at all.  
- Good morning - Sherlock didn't say anything - Hey, d'ya know what happened yesterday? 'Cause I don't feel too well -  
- Long story. All you need to know is that you've been drugged and today I catched our murderer -  
- Wow. So I'm drugged. Fantastic - John yawned. Sherlock murmured something about an experiment and went to the kitchen. John followed him with his eyes.  
- Sherlock, is my impression or you're not walking properly? Did something happen? -  
- Nothing at all -


End file.
